Chronic neurogenic pain inducing chemiluminescence of mitochondrial associates in cardiomyocytes.
Authors: Ekaterina I. Surikova, Irina V. Neskubina, Elena M. Frantsiyants, Natalia D. Cheryarina, Alla I. Shikhlyarova, Valeria A. Bandovkina, Ludmila A. Nemashkalova, Irina V. Kaplieva, Lidia K. Trepitaki, Polina S. Kachesova, Ludmila P. Kuchkina, Viktoriya L. Volkova, Yulia V. Ulianova, Iuliana S. Shatova, Olga V. Pandova, Oleg I. Kit
Journal: Journal of Clinical Oncology (2022)

e21560 Background: Mitochondrial dysfunction is has a significant impact on the development of heart disease and is a characteristic feature of the heart physiopathology. Our purpose was to analyze some mechanisms of apoptosis regulation and self-organization in the mitochondria of the heart cells in mice with melanoma growing in presence of chronic neurogenic pain (CNP). Methods: The study included female C57BL/6 mice (n = 105) divided into groups: intact animals (n = 21); controls (C, n = 21) with a CNP model created by bilateral sciatic nerve ligation under xylazine/zoletil anesthesia; main group (CNP+B16/F10, n = 63) with B16/F10 melanoma transplanted after CNP creation. After decapitation, mitochondria of the heart were isolated by differential centrifugation. Levels of cytochrome C (ng/mg of protein), caspase 9 (ng/mg of protein), Bcl-2 (ng/mg of protein), AIF (ng/mg of protein), Ca 2+ (mmol/g of protein) were determined in mitochondrial samples by ELISA. Results: CNP downregulated levels of Ca 2+ by 3.2 times, Bcl-2 by 1.3 times (p &lt; 0.05) and caspase 9 by 1.5 times (p &lt; 0.05), compared to intact mice. AIF levels, on the contrary, were elevated by 2.3 times, and cytochrome C did not differed statistically significantly from intact values. After a week of B16/F10 growth in presence of CNP, levels of Ca 2+ in the mitochondria of the heart increased by 5.3 times relative to C values. Further on, Ca 2+ decreased to almost undetectable values. The AIF levels changed abruptly: after 1 week it increased by 3.7 times, after 2 weeks it declined to C levels, and after 3 weeks it became 5.2 times lower than in C and 2.3 times lower than in intact animals. Bcl-2 and cytochrome C changed similarly: Bcl-2 after 1 week of melanoma growth in presence of CNP increased 1.7 times (p &lt; 0.05) compared to C, and then after 2-3 weeks it declined and became on average 2.2 times lower than in the mitochondria of the C group; levels of cytochrome C after 1 week did not differed significantly from the values in C, and after 2-3 weeks they decreased by 2.2 times. The levels of caspase 9 in CNP+B16/F10 were on average 2.4 times higher than C values throughout the study. The cold light of high brightness - chemiluminescence was recorded in samples of mitochondrial suspension after 2-3 weeks of CNP+B16/F10. The glow in heart mitochondrial samples was accompanied by bright flashes and a 10-15 second intense white glow with a gradual fading and settling of a large filamentous aggregation of mitochondria on the substrate layer. CNP contributed to the energy supply system blocking in the energy systems of cardiomyocytes. Conclusions: Mitochondrial mechanisms of apoptosis and self-organization of subcellular energy structures in the conditions of malignant tumor growth in presence of CNP are mediated by disruption of polyenzymatic apoptosis regulation systems, and a high level of oxidative stress that induces chemiluminescence of cardiomyocyte mitochondrial associates.